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Privacy Policy

Last Updated: August 9, 2026

At chessrank.org, we believe chess tools should be fast, free, and respect your privacy. Here is exactly how we handle data.

1. Overview & Privacy Philosophy

At chessrank.org ("chessrank", "we", "us"), privacy is built into our architecture. Unlike commercial platforms that profit from selling targeted ads or selling user profiles to third-party data brokers, chessrank.org operates without advertising tracking.

This Privacy Policy details the minimal data we collect, how it is used, where it is stored, and your rights under privacy legislation including the General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA).

Who is responsible for your data. chessrank.org is built and operated by Matej Staif, an individual based in the Czech Republic, who is the data controller for the processing described here. You can reach the controller at any time at [email protected]. We are not required to appoint a Data Protection Officer, so this address reaches the controller directly.

2. Data We Do NOT Collect

To be completely transparent about what we do not do:

  • No Commercial Ad Tech: We do not run Google AdSense, Quantcast CMP, or programmatic advertising exchanges. We do not place ad cookies or share your profile with ad tech partners.
  • No Data Monetization: We never sell, rent, trade, or share your personal data or chess history with third parties for marketing purposes.
  • No Cross-Site Tracking: We do not track your activity on external websites.

3. Information We Collect & How It Is Used

A. Privacy-Focused Analytics (Cookieless)

We collect basic aggregate usage telemetry using Umami Analytics (s.chessrank.org/cr.js) and Vercel Analytics to keep the platform reliable:

  • Cookieless Operation: No persistent tracking cookies or advertising identifiers are stored in your browser for analytics.
  • No visitor profile: Your IP address is used only transiently, to derive a non-reversible daily hash that distinguishes one visit from another, and is not stored alongside the resulting statistics. We measure total page visits, popular tools (e.g. Free Game Review, Blunder Trainer), approximate country, and site performance — never an individual browsing history.
  • Production only: Analytics run exclusively on the live site; development and preview builds send nothing at all.

B. Account Information (Registered Users)

You can use chessrank.org as a guest without registering. If you choose to create an account:

  • Account Credentials: We store your email address and username securely via Supabase Auth.
  • Chess Training Progress: Your saved custom puzzles, solved blunder history, rating progress, and bookmarked game reviews are stored so you can access them across devices.

C. Public Chess Data Import

When using tools like Free Game Review or Opponent Prep, you may enter a public Chess.com or Lichess username or PGN string. We fetch publicly available game archives via official open APIs to generate your requested analysis.

D. Local Storage on Your Device

To deliver an instant UI without server roundtrips, your theme (dark/light), piece style, sound volume, board preferences, and local engine cache are saved locally in your browser's localStorage and IndexedDB. You can clear this data at any time via your browser settings or Settings.

4. In-Browser Stockfish Engine Computation

When you run game analysis or solve tactical blunders, the Stockfish engine executes directly inside your web browser via WebAssembly (WASM).

Local Computation: Your computer or smartphone handles the engine evaluation locally. Move calculations stay on your device and are not uploaded to server infrastructure unless you explicitly save a game review to your account.

5. Third-Party Processors and Recipients

We use the following providers strictly to host and operate the Platform. Each acts as a processor on our behalf, processes data only to maintain uptime, security and performance, and is bound by its own data processing agreement:

  • Vercel Inc.: Global edge hosting, static content delivery and serverless runtime. Vercel processes connection metadata (including IP address) as part of serving every request, and provides the aggregate Vercel Analytics and Speed Insights measurements described in section 3.
  • Supabase: Encrypted cloud database and authentication for registered accounts.
  • Umami Cloud: Cookieless analytics. The measurement script is served from our own s.chessrank.org subdomain, but the analytics service itself runs on Umami’s infrastructure — it is not self-hosted by us.
  • Cloudflare: Operates the s.chessrank.org proxy that forwards analytics events to Umami, and therefore handles the connection (including IP address) in transit.
  • Web3Forms: Delivers the optional feedback form in Settings. If you submit feedback, the message — and any contact details you choose to include — is transmitted through Web3Forms to reach us by email.
  • Stripe: If you choose to make a voluntary donation, you leave the Platform and complete the payment on Stripe’s own hosted checkout. Stripe acts as an independent controller for that transaction under its own privacy policy. We never receive or store your card details.

We fetch public game archives from the Chess.com and Lichess public APIs when you ask us to. Those requests are made from our infrastructure using the username you supply; we do not send them any personal data about you.

6. International Data Transfers

Some of the providers listed above operate infrastructure outside the European Economic Area, including in the United States. Where personal data is transferred outside the EEA, that transfer is covered by the safeguards those providers offer — in practice the European Commission’s Standard Contractual Clauses and, where applicable, the EU–US Data Privacy Framework.

7. Legal Bases for Processing

Under Article 6 of the GDPR, every processing operation needs a legal basis. Ours are:

  • Contract (Art. 6(1)(b)): Creating and running your account, storing your training progress, and delivering the analysis you request. Without this data the service you asked for cannot be provided.
  • Legitimate interests (Art. 6(1)(f)): Aggregate, cookieless audience measurement, keeping the Platform secure and available, and preventing abuse. We use these interests only in a form that does not identify you individually, which is why no consent banner is required.
  • Consent (Art. 6(1)(a)): Sending us optional feedback, and appearing on a public leaderboard under a display name you choose. You can withdraw consent at any time, which does not affect processing carried out beforehand.
  • Legal obligation (Art. 6(1)(c)): Retaining records where the law requires it, for example in connection with donations.

Strictly necessary storage — your theme, language, sound and board preferences, and your login session — is exempt from the consent requirement in Article 5(3) of the ePrivacy Directive because it delivers a service you explicitly requested. We store no advertising or cross-site tracking identifiers of any kind, which is why chessrank.org shows no cookie consent pop-up.

8. Data Security & Retention

All network communication with chessrank.org is encrypted in transit using Transport Layer Security (TLS/HTTPS). Account data is encrypted at rest, and passwords are protected using industry-standard cryptographic hashing algorithms.

We keep data no longer than it is useful for the purpose it was collected for:

  • Account and training data: kept while your account is active. Deleting your account removes it.
  • Analytics: aggregate, non-identifying counts only; no visitor-level profile is built or retained.
  • Feedback messages: kept only as long as needed to deal with what you wrote to us.
  • Guest data: never leaves your device, and is cleared whenever you clear your browser storage.

9. Your Rights under GDPR & CCPA

Regardless of where you live, we respect your fundamental data rights:

  • Right to Access: You can request a copy of all personal data associated with your account.
  • Right to Rectification: You can update your profile and preferences in Settings.
  • Right to Erasure ("Right to be Forgotten"): You can delete your account and all associated saved data at any time, directly in Settings.
  • Right to Data Portability: You can export your saved game reviews and puzzle progress.
  • Right to Object and to Restrict Processing: You can object to processing we carry out on the basis of legitimate interests, and ask us to restrict processing while an objection or a correction is being resolved.
  • Right to Withdraw Consent: Where we rely on consent, you can withdraw it at any time.

Right to lodge a complaint. If you believe we have handled your data unlawfully, you can complain to a data protection supervisory authority — in the Czech Republic, the Office for Personal Data Protection (Úřad pro ochranu osobních údajů, uoou.gov.cz), or the authority in your own country of residence.

For California residents. We do not sell your personal information, and we do not share it for cross-context behavioural advertising, as those terms are defined by the CCPA/CPRA. Because we run no advertising, there is nothing to opt out of. Exercising any right above will never result in a worse or more limited service.

No automated decision-making. Your chess ratings, accuracy scores and move classifications are produced by a chess engine to help you train. They are not used to make any decision that produces a legal or similarly significant effect on you within the meaning of Article 22 of the GDPR.

To exercise any of these rights, email [email protected]. We answer without undue delay and in any case within one month.

10. Children's Privacy

chessrank.org is designed for chess players of all ages. We do not knowingly collect personal identifiable information from children under the age of 13 (or 16 in applicable European jurisdictions) without parental consent. If you believe a child has provided us with personal information, please contact us so we can immediately delete it.

11. Updates to This Privacy Policy

We may update this Privacy Policy periodically to reflect new features, performance improvements, or legal requirements. Updates will be posted on this page with a revised "Last Updated" date.

12. Contact Us

If you have questions, feedback, or data privacy requests regarding this policy, please reach out to us via email at [email protected] or visit our Behind chessrank.org page.